Stabilized water-in-oil emulsions utilizing minor amounts of oil-soluble polymers

ABSTRACT

An additive and method of stabilizing and decreasing sediment in a water-in-oil emulsion where the aqueous discontinuous phase contains a water-soluble vinyl addition polymer, comprising an oil-soluble polymer added to the continuous phase in the amount of about 0.1-1% by weight based on the total polymer emulsion. Preferred water-in-oil emulsions include those containing polyacrylamide, polyacrylic acid predominantly in salt form, and copolymers thereof; and preferred oil-soluble polymers include polyisobutylene, polybutadiene, Betaprene H, poly(t)butylstyrene, and natural rubber. The additive and method are useful for redispersing such emulsions.

United States Patent Slovinsky et al.

STABILIZED WATER-IN-OIL EMULSIONS UTILIZING MINOR AMOUNTS OF OIL-SOLUBLE POLYMERS Inventors: Manuel Slovinsky, Woodridge;

Roger C. Ryan, Chicago; Kenneth G. Phillips, River Forest, all of I11.

Nalco Chemical Company, Oak Brook, 11].

Filed: Mar. 15, 1974 Appl. No.: 452,083

Assignee:

References Cited UNITED STATES PATENTS 11/1971 Anderson et a1 260/29.6 B

5/1972 Baker et al. 260/34.2 12/1973 Hicks 260/34.2

[ Oct. 28, 1975 2/1974 Clarke et al. 5/1974 Burdette et a1.

OTHER PUBLICATIONS Noll-Chemistry and Technology of Silicones, Academic Press, N.Y.( 1968), p. 193.

[5 7 ABSTRACT An additive and method of stabilizing and decreasing sediment in a water-in-oil emulsion where the aqueous discontinuous phase contains a water-soluble vinyl ad dition polymer, comprising an oil-so1uble polymer added to the continuous phase in the amount of about 0.1-1% by weight based on the total polymer emulsion. Preferred water-in-oil emulsions include those containing polyacrylamide, polyacrylic acid predominantly in salt form, and copolymers thereof; and preferred oil-soluble polymers include polyisobutylene, polybutadiene, Betaprene H, poly(t)-butylstyrene, and natural rubber. The additive and method are useful for redispersing such emulsions.

2 Claims, No Drawings STABILIZED WATER-IN-OIL EMULSIONS UTILIZING MINOR AMOUNTS OF OIL-SOLUBLE POLYMERS A recent development in water-soluble polymer chemistry has been the appearance of water-soluble vinyl addition polymers which are dispersed as a waterin-oil emulsion which may be then conveniently packaged and inverting these emulsions in water for use. This technology is encompassed in U.S. Pat. No. 3,624- ,019 Anderson et al. (Nalco) and the polymerization of the monomers in a water-in-oil polymerization method for the same type polymers is set out in U.S. Pat. No. 3,284,393 Vanderhoff (Dow), and these two patents are hereby incorporated by reference for the specific reasons set out.

Of particular applicability in water treatment are water-soluble polymers formed from acrylamide or acrylic acid and salts thereof which are either homopolymers or copolymers. Specific examples of acrylic pol ymers which are preferred for this invention are homopolymers of acrylamide; a copolymer of acrylamide and 7% methacrylic or acrylic acid; a copolymer of acrylamide and 30% acrylic acid; and homopolymers of acrylic acid; all the acids being predominantly in the salt form.

The word salt where used in this specification is intended to include preferably alkali metal, ammonium, and amine salts such as, for example, the sodium and potassium salts.

Where the terms acrylic and polyacrylic acid are used in this specification they are intended to include both the free acid and the salts noted above.

The term polyacrylate likewise denoted predominantly the preferred salts as above and a preferred variety is where alternating treatment by base and then acid produces an acrylate which is predominantly in a salt form but contains a minority of free acid groups in the polymer structure.

In the packaging or shelf life, particularly of the polyacrylamides in water-in-oil emulsions and in containers, it has been found that a certain amount of sediment is produced on standing and it is a function of this invention to provide a method and compositions for decreasing this sediment and making it more easily dispersed. Additionally, the additives have been found to decrease the time necessary for redispersing original polymers constituting and packaging the water-in-oil emulsion.

THE OIL-SOLUBLE POLYMERIC DISPERSANTS The present additives which are added to the oil phase of the invert emulsion are oil-soluble polymers which function to hinder the settling of the polymer which is dispersed in the water phase so that it does not settle out rapidly in a container. For this purpose certain specific oil-soluble polymers have been found to stabilize the emulsion and to give decreased settling propensities and decreased sediment. Among the preferred polymers are the polyisobutylenes, polybutadiene, Betaprene H, poly(t)butylstyrene, and natural rubbers. Polymers which are unsuitable for the present invention include polyethylene and polypropylene which do not function in this milieu due to insufficient solubility.

The polymeric oil-soluble additive may be introduced into the system at any time but preferably just after the formation of the basic water-in-oil emulsion polymer.

It has been further found that with polyisobutylene, the materials may be utilized in aromatic solvents or aliphatic, type solvents such as a high purity isoparaffin and that the molecular weight of the oil-soluble polymer may be selected, as for isobutylenes, from molecular weights of 5 million, 1.3 million, and down to molecular weight of 380,000. However, the higher molecular weight polyisobutylenes are more effective and a minimum of 1 million molecular weight is preferred. it is apparent that some efficiency as a stabilizer or dispersant is sacrificed in favor of increased rate of solubilization as the molecular weight is lowered and specially below the preferred 1 million molecular weight. The molecular weight carryover has also been extended to other suitable oil-soluble polymers in that an operable range of about 300,000 to 6 million has been observed.

Of particular adaptability to this process has been the utilization of 0.3% polyisobutylene of molecular weight of 5 million utilized here as a 3% solution. The basic polymer is conveniently available commercially under the trade designation Oppanol B-200 (BASF), molecular weight 5 million, and utilized in Espesol (Exxon), an aromatic hydrocarbon solvent. Additionally, the Oppanol B-l00, molecular weight 1.3 million, and Oppanol B-50, molecular weight 380,000, may be utilized where the faster solubilization of the lower molecular weight polymers is required or desired.

The dispersion or solution of the oil-soluble polymer may be effected in any suitable hydrocarbon solvent. Of particular utility are Espesol, an aromatic solvent, and lsopar-M, an aliphatic solvent which is a highly purified isoparaffin hydrocarbon product, both products of Exxon. The selection of the solvent is not critical with the exception that it perform adequately the function denoted.

Explanation of the favorable effects of adding oilsoluble polymers to the inverse emulsion systems of the present invention lies along two lines of thought. First, by the addition of polymers to the continuous phase (oil), sediment is slower to form on the bottom of the container. Secondly, apparently there is an effect on the particle-to-particle interaction in that sediment on the bottom is easier to redisperse, which fact may be in some manner associated with the change of viscosity of the continuous oil phase.

DOSAGE The dosage of the oil-soluble polymer added to the continuous phase may be in the amount of 0.l-l% by weight based on the total water-in-oil polymer emulsion and preferably in the amount of 0.3.75% by weight on the same basis. The most important parameter is the lower value for the range since this value determines the least amount of additive necessary to stabilize and redisperse the basic water-in-oil emulsion.

EXAMPLE 1 Experimental Procedure The following testing protocol was designed to compare the results of four polyacrylamide and/or polyacrylate water-in-oil emulsions which had been prepared according to the procedure of U.S. Pat. No. 3,624,0l9Anderson (ante) and to which certain oilsoluble additives were added and measuring the effect on emulsion stability.

The test procedure consisted of centrifuging 50g of the experimental emulsion and an untreated control at acrylic acid sodium salt.

Polymer C is a homopolymer of acrylamide. Polymer D is a copolymer of acrylamide and 7% methacrylic or acrylic acid sodium salt.

high speed for ten minutes, then inverting the centri- 5 P lym r A-D are g molecular we gh n rfuge tube for one minute to measure the amount of soluble polymers of molecular weight 1 million to 7 emulsion to flow from the tube in that period. This milli n. amount of flow was then expressed as a percentage of Oppanol B-200 (BASF) is a polyisobutylene with a the original 50g present. The test by centrifuge gave molecular weight of 5 million. consistent results; that is, a given control or experimenl0 Oppanol B-lOO (BASF) is a polyisobutylene with a tal sample would give the same percent to flow num molecular weight of 1.3 million. bers repeatedly in the same type of centrifuge tubes. Oppanol B-50 (BASF). is a polyisobutylene with a 1n the following Tables 1-6, results are expressed for molecular weight of 380,000. the addition of the oil-soluble polymer polyisobutylene Espesol (Exxon) is an aromatic hydrocarbon solvent. (Oppanol B) in several molecular weights with four lsopar M (Exxon) is a high purity isoparraffin solpolymer emulsions selected from polyacrylamides, vent. polyacrylamides/acrylates, and homopolyacrylates Results: From a consolidated summary of Tables 1-6, and salts thereof, and additionally in an aromatic hyit would appear that the addition of the oil-soluble poldrocarbon solvent (Espesol) and an aliphatic hydrocarymer, in this case polyisobutylene in the dosage level of bon solvent (lsopar-M). 0.10.5% by weight, increased the pourables of the Table 7 shows additional test results involving sepabasic water-soluble polymer substantially. In many rate polymers; namely, poly(t)butylstyrene (TBS), natcases this increase was from a range in the 's (e.g., ural rubber latex (NRL), and betaprene H-l00 Reich- 37%) to a range in the s (e.g., hold, showing the increase in flow level wherein the In other experiments in Table 7 a carryover of inweight percent of oil-soluble polymer in the emulsion 25 crease in pourables with Polymer A was observed relatrises to the level of 0.24-0.48. ing to poly(t)butylstyrene (TBS), a natural rubber latex Definitions relative to Tables 1-6: with 65% solids (NRL), and Betaprene H- (Reich- Polymer A is a homopolymer of sodium acrylate. hold), which is a hydrocarbon resin derived from a nar- Polymer B is a copolymer of acrylamide and 30% row range of monomeric olefins and di-olefins.

TABLE 1 THE STABILIZATION OF INVERTED LATICES BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-200) 1N lSOPAR M LATEX PlB Polymer B Polymer C Polymer D Level of Source PlB Addi- (Conc. Solids Solids Solids tion (Wt. in Viscosity Percent Original Viscosity Percent Original Viscosity Percent Original on Latex) lsopar) (CPS) Pourables Polymer (CPS) Pourables Polymer (CPS) Pourables Polymer Blank 1100 46.3 31.0 1400 70.5 34.0 738 64.9 31.5

TABLE 2 THE STABlLlZATlON OF LIQUID POLYMERS A AND B BY THE ADDlTlON OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL 1.3-200) 1N ESPESOL LATEX PlB Polymer A Polymer B Level of Source P 1B Addi- (Soln. Percent Percent tron (Wt. cone. in Viscosity Percent Original Viscosity Percent Original on Latex) Espesol (CPS) Pourables Polymer (CPS) Pourables Polymer Blank 1250 28.6 31.0 1175 46.3 31.0

TABLE 2 Continued THE STABILIZATION OF LIQUID POLYMERS A AND B BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-200) IN ESPESOL Level of P18 Addi' tion (Wt. on Latex) THE STABILIZATION OF LIQUID POLYMERS C AND D BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-ZOO) IN ESPESOL LATEX PIB Polymer C Polymer D Level of Source PIB Addi- (Soln. Percent Percent tion (Wt. conc. in Viscosity Percent Original Viscosity Percent Original on Latex) Espesol (CPS) Pourables Polymer (CPS) Pourables Polymer Blank 1338 72.6 34.0 763 68.8 30.7

TABLE 3 THE STABILIZATION OF THE LIQUID POLYMERS A, C, AND D BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-IOO) IN ISOPAR M LATEX PIB Polymer A Polymer C Polymer D Level of Source PIB Addi- (Wt. Percent Percent Percent tion (Wt. in Viscosity Percent Original Viscosity Percent Original Viscosity Percent Original on Latex) Isopar) (CPS) Pourables Polymer (CPS) Pourables Polymer (CPS) Pourables Polymer Blank 1325 34.4 31.0 1388 70.7 34.0 813 66.9 31.5

TABLE 4 THE STABILIZATION 0F LIQUID POLYMERS A, C, AND D BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-IOO) IN ESPESOL LATEX PIB Polymer A Polymer C Polymer D Level of Source PIB Addi- (Wt.% Percent Percent Percent tion (Wt. in Viscosity Percent Original Viscosity Percent Original Viscosity Percent Original on Latex) Espesol) (CPS) Pourables Polymer (CPS) Pourables Polymer (CPS) Pourables Polymer Blank 1363 31.7 31.0 1425 70.6 34.0 1325 67.6 31.5

TABLE 5 THE STABILIZATION OF THE LIQUID POLYMERS A. C. AND D BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-SO) IN ISOPAR M LATEX PIB Polymer A Polymer C Polymer D Level of Source P IB Addi- (Wt.% Percent Percent Percent tion (Wt. in Iso- Viscosity Percent Original Viscosity Percent Original Viscosity Percent Original on Latex) par M) (CPS) Pourables Polymer (CPS) Pourables Polymer (CPS) Pourables Polymer Blank 1388 38.7 31.0 1413 70.5 34.0 825 64.6 31.5

TABLE 6 THE STABILIZATION OF LIQUID POLYMERS A. C. AND D BY THE ADDITION OF A SOLUTION OF POLYISOBUTYLENE (OPPANOL B-50) IN ESPESOL LATEX PIB Polymer A Polymer C Polymer D Level of Source PIB Addi- (Soln. Percent Percent Percent tion (Wt. in Viscosity Percent Original Viscosity Percent Original Viscosity Percent Original on Latex) Espesol) (CPS) Pourables Polymer (CPS) Pourablcs Polymer (CPS) Pourables Polymer Blank 1350 36.1 31.0 1400 70.2 34.0 813 63.9 31.5

TABLE 7 Wt on Wt. to Flow Latex Viscosity Viscosity After 10 min. Additive (Wt. (Liquid Before Additive After Additive Centrifugation to Consistency on Polymer) Polymer) (3 12 rpm) (3 12 rpm) (50g Sample) Flow of Residue 0.00% TBS .00 2800 cps 18.7g 37.4% Thick 0.25% TBS .08 2800 cps 25.1g 50.0% 0.50% TBS o .16 3250 cps 30.1g 60.6% Flows 0.75% TBS .24 3700 cps 34.6g 69.2% 1.00% TBS .32 4060 cps 37.2g 74.5% 1.50% TBS .48 4350 cps 35.5g 71.0% 0.25% NRL .08 3720 cps 25.5g 51.0% Thick 0.50% NRL .16 4350 cps 26.9g 54.0% Flows 0.75% NRL .24 5360 cps 29.6g 59.0% 1.00% NRL .32 6600 cps 30.7g 61.4% 1.50% NRL .48 9500 cps 22.4g 44.7% 0.25% H-lOO .08 2800 cps 18.9g 37.8% V. Thick 0.75% I-l-IOO .24 2680 cps 21.7g 43.4% 1.00% H400 .32 2500 cps 21.8g 43.5%

TBS poly(tertiary)butylstyrenc NRL natural rubber latex with 65?! solids H400 Betuprcne H-l00 (Rcichhold). a polymer of m.p. 100C. (Ball & Ring) derived from a narrow hydrocarbon cut consisting principally ofa mixture of monoand di-olefin monomers Two drums of Polymer A were blended and mixed. Both drums were then refilled with the homogenous product and to one of them was added 1% polyisobutylene. Using the same material, two 100 cc glass tubes were used as a double monitor.

Inspection of both drums after days indicated that the amount of settled solids in the untreated drum was considerably higher (about 9 inches) than in the treated sample (less than one-fourth inch).

Using light duty air driven mixers both drums were mixed and viscosities were measured as a function of time. Brookfield viscosities of the untreated Polymer A was 2,150 cps compared to 1,150 cps for the treated sample. It was possible to reconstitute the treated Polymer A to its original viscosity of 1,150 cps in less than 10 minutes. It was not possible to measure the viscosity of the untreated sample because of the large lumps and consequent uneven distribution of the product. Both drums were mixed for a total of 2 hours; no improvement was observed in the untreated sample.

Similar results were observed in the double monitor 100 cc tubes.

Polymer A, as noted ante in Example 1, is a homopolymer of sodium acrylate with a molecular weight of about 2 million.

We claim:

1. In a method of stabilizing and decreasing sediment formation in a water-in-oil emulsion wherein the water phase contains a water-soluble vinyl addition polymer in a continuous oil phase, the step consisting of adding an oil-soluble polymer to the continuous phase in an amount of about 0.11% based on the total weight of the emulsion wherein the oil-soluble polymer selected from at least one member of the group consisting of polyisobutylene, polybutadiene, poly(tertiary) butystyrene and natural rubber, and wherein said oil-soluble polymer has a molecular weight in the range of about 300,000 to 6 million dispersed in a suitable organic solvent.

2. A water-in-oil emulsion of a water-soluble vinyl addition polymer which also contains as an additive about 0.ll% by weight of an oil-soluble polymer added to the continuous phase wherein the weight percent of said oil-soluble polymer is based on the total emulsion and wherein the oil-soluble polymer selected from at least one member of the group consisting of polyisobutylene, polybutadiene, poly(tertiary) butylstyrene and natural rubber, and wherein said oil-soluble polymer has a molecular weight in the range of about 300,000 to 6 million dispersed in a suitable organic solvent. 

1. IN A METHOD OF STABILIZING AND DECREASING SEDIMENT FORMATION IN A WATER-IN-OIL EMULSION WHEREIN THE WATER PHASE CONTAINS A WATER-SOLUBLE VINYL ADDITION POLYMER IN A CONTINUOUS OIL PHASE, THE STEP CONSISTING OF ADDING AN OIL-SOLUBLE POLYMER TO THE CONTINUOUS PHASE IN A AMOUNT OF ABOUT 0.1-1% BASED ON THE TOTAL WEIGHT OF THE EMULSION WHEREIN THE OIL-SOLUBLE POLYMER SELECTED FROM AT SEAST ONE MEMBER OF THE GROUP CONSISTING OF POLYISOBUTYLENE, POLYBUTADIENE, POLY(TERTIARY) BUTYSTYRENE AND NATURAL RUBBER, AND WHEREIN SAID OIL-SOLUBLE POLYMER HAS A MOLECULAR WEIGHT IN HE RANGE OF ABOUT 300,000 TO 5 MILLION DISPERSED IN A SUITABLE ORGANIC SOLVENT.
 2. A water-in-oil emulsion of a water-soluble vinyl addition polymer which also contains as an additive about 0.1-1% by weight of an oil-soluble polymer added to the continuous phase wherein the weight percent of said oil-soluble polymer is based on the total emulsion and wherein the oil-soluble polymer selected from at least one member of the group consisting of polyisobutylene, polybutadiene, poly(tertiary) butylstyrene and natural rubber, and wherein said oil-soluble polymer has a molecular weight in the range of about 300,000 to 6 million dispersed in a suitable organic solvent. 